[ 57 * ] 
If. A Letter from Mr. John Winthrop, Hoi- 
lifian Lrofejfor of Mathematics and Aftro- 
nomy at Cambridge in New-England, to 
G, Mortimer, M. \D. Sec . R. S. concerning 
the Tranlit of Mercury over the Sun, April 
i\. 1740. and of an Eclipfe of the Moon, 
Dec. 21.1 740. 
SIR, 
r<w Nov. 3. '~“T~ 1 H o U G H I have not the Honour 
1 to be known to you, I flatter my- 
felf you will excufe the Freedom of this Letter, fince 
t lie Defign of it is to lay before you an Obfervarion 
which, I hope, may be of feme Ufc in Aflronomy. 
I11 Confidence of this, I take the Liberty to inform 
you, that, on the 21ft o i April 1740. I had an Oppor- 
tunity to obferve Mercury, then near his defeending 
Node, tranfiting the Sun’s Disk. Being advertifed 
by the Calculations of that excellent Aflronomer 
Dr. Halley, that the former Part of this Tranfit would 
be vifible in our Horizon, I was refolved to obferve 
it in the befl: manner I could, with thofe few Inftru- 
naents I was furnifhed with; which were only thole 
I had received from my P;edecelfor Mr Hfaac Green- 
wood, and are the fame that are mentioned by the 
late Mr. Thomas Robie in c Philofophical Tranf aUions 
N° 382. being a 24 Foot Telelcope, another of Eight 
Foot, and a brafs Quadrant of Two Foot Radius , 
fitted with telefcopic Sights, and having crofs Hairs 
fixed in the Focus of the Glafles. All thefe I got in 
Readi- 
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